The present invention relates to an improvement on a cellular phone, and in particular, to an improvement for attaining high sound quality of the cellular phone.
FIG. 1 is a perspective view showing an example of a generally used conventional cellular phone. As shown in FIG. 1, the conventional cellular phone is provided with a display 101 (implemented by an LCD (Liquid Crystal Display) etc.), operation buttons 102, a speaker 103 and a microphone 104 which are placed on the same side of a housing 100 (outer casing of the cellular phone).
In the following, the operation of the conventional cellular phone of FIG. 1 will be explained referring to FIG. 2. FIG. 2 is a block diagram showing an example of the composition of the conventional cellular phone of FIG. 1. The cellular phone 200 of FIG. 2 receives signals transmitted from radio base stations by its antenna 201. The signal received by the antenna 201 is supplied to a radio section 202. After frequency conversion and channel selection are carried out by the radio section 202, the received signal is supplied to a modulation/demodulation section 203 to be demodulated. The demodulated signal is supplied to a sound processing section 204 and is outputted as a received sound signal. The received sound signal is supplied to a received sound amplifier 205, amplified by the received sound amplifier 205, supplied to the speaker 103, and is outputted as received sound.
Meanwhile, voice of the user inputted to the microphone 104 is converted by the microphone 104 to a sound signal and is supplied to a transmitted sound amplifier 208. The sound signal is amplified by the transmitted sound amplifier 208 and the amplified sound signal is inputted to the sound processing section 204 and is supplied to the modulation/demodulation section 203 to be modulated. The modulated signal is supplied to the radio section 202 and is transmitted from the antenna 201 by use of a preset frequency and power.
The radio section 202, the modulation/demodulation section 203 and the sound processing section 204 operate under control of a control section 209. The control section 209, which is capable of receiving signals from the radio section 202, the modulation/demodulation section 203, the sound processing section 204, a display section 210 (including the display 101) and an operation section 211 (including the operation buttons 102), controls the operation of the components by sending control signals to them.
However, in such conventional cellular phones, the space for mounting the speaker 103 is being narrowed due to the upsizing of the display 101 and the operation buttons 102 of these days, and it is becoming more and more difficult in the actual situation to use a speaker having an enough diameter and realize wide-range and high-volume-level sound reproduction. On the other hand, if a large-diameter speaker is forcibly employed in the cellular phone, the sizes of the display 101 and the operation buttons 102 are necessitated to be limited and thereby the usability of the cellular phone is impaired.
Further, the conventional cellular phone is provided with only one speaker 103 so as to be used for conversation, therefore, stereophonic sound reproduction of music etc. is impossible by the cellular phone despite the tendencies of cellular phone users of today to download music or tunes (as MP3 data etc.) from the Internet.
A cellular phone capable of receiving radio broadcasting and reproducing it in stereo sound has been proposed in Japanese Patent Application Laid-Open No.HEI10-233826. However, the stereo sound reproduction by the conventional cellular phone is possible only through earphones. Stereophonic sound reproduction through speakers is not realized by the conventional cellular phone.
It is therefore the primary object of the present invention to provide a cellular phone realizing stereophonic sound reproduction of music etc. through speakers without impairing the usability of the cellular phone.
Another object of the present invention is to provide a cellular phone capable of employing a large-diameter speaker and thereby realizing wide-range and high-volume-level sound reproduction, without impairing the usability of the cellular phone.
In accordance with a first aspect of the present invention, there is provided a cellular phone comprising a speaker and a microphone that are implemented by a first signal-vibration transducer and a second signal-vibration transducer that are functionally equivalent. When the cellular phone is used for conversation, the first signal-vibration transducer functions as the speaker and the second signal-vibration transducer functions as the microphone. When the cellular phone is used for sound reproduction, the first signal-vibration transducer and the second signal-vibration transducer function in cooperation as stereo speakers.
A speaker is a device for outputting sound by transducing an electric signal into vibration energy of a diaphragm, while a microphone is a device for outputting an electric signal by transducing vibration given to a diaphragm into electric energy. Therefore, the speaker and the microphone are basically equivalent in electromechanical structure and they can be used compatibly. Therefore, in the present invention, the speaker and the microphone are implemented by equivalent signal-vibration transducers. One of the signal-vibration transducers is used exclusively as a speaker, while the other signal-vibration transducer is used as a microphone (when the cellular phone is used for conversation) and a speaker (when the cellular phone is used for sound reproduction), thereby ordinary conversation (using a speaker and a microphone) and stereophonic sound reproduction (using two speakers simultaneously) are both realized in a cellular phone having only two signal-vibration transducers.
In accordance with a second aspect of the present invention, in the first aspect, a display and operation buttons of the cellular phone are placed on a side of a housing of the cellular phone, and the speaker and the microphone are placed apart on the other side of the housing of the cellular phone.
By such placement of the speaker and the microphone, the enlargement of the diameters of the speaker and the microphone is attained easily, without being affected by the placement of the display and the operation buttons. Therefore, wide-range and high-volume-level sound reproduction using large-diameter speakers can be realized. Further, due to the removal of the speaker and the microphone, the sizes of the display and the operation buttons can be enlarged independently of the enlargement of the speaker and microphone, thereby a cellular phone having improved viewability and operability can be provided.
In accordance with a third aspect of the present invention, in the second aspect, the housing includes: a display section including the display; an operation section including the operation buttons; and a hinge section connecting the display section and the operation section so that the cellular phone can be folded into a folded state in which the display faces the operation buttons and can be unfolded into an unfolded state in which the display is apart from the operation buttons.
In a folding cellular phone having such composition, the speaker is placed on the back (outer side) of the display section and the display is placed on the front (inner side) of the display section, while the microphone is placed on the back (outer side) of the operation section and the operation buttons are placed on the front (inner side) of the operation section. By such placement and structure, a proper distance can be kept between the speaker and the microphone and thereby the use is allowed to make conversations comfortably. The user is also allowed to put (stand) the folding cellular phone (with its flank facing downward) on a desk etc. stably (by setting a proper angle between the display section and the operation section) and thereby fully enjoy the stereophonic sound reproduction. The user faces the front of the housing (the display and the operation buttons) when the user pushes buttons, checks display, etc. before making a conversation, whereas the user faces the back of the housing (the speaker and the microphone) during the conversation. Therefore, the user is required to flip the cellular phone for starting a conversation, however, the flipping can be done easily, only by rotating the cellular phone by a half-turn around the major axis (long axis) of the cellular phone. The user does no have to turn the cellular phone upside down, therefore, the cellular phone can be handled and used easily, especially in narrow and limited spaces. Incidentally, it is also possible to place the microphone on the back of the display section and place the speaker on the back of the operation section. However, such composition is less advantageous in narrow and limited spaces since the upside-down turn of the cellular phone becomes necessary.
In accordance with a fourth aspect of the present invention, in the third aspect, the housing is designed so that the angle between the display and the operation buttons in the unfolded state can be set larger than 180xc2x0.
By such composition, the angle between the speaker and the microphone can be set less than 180xc2x0, thereby the microphone and speaker can properly be placed at the mouth and ear of the user along the contour of the user""s head, letting the user have conversations easily and comfortably. When the cellular phone is used for sound reproduction, the stability of the cellular phone that is stood (with its flank facing downward) on a desk etc. increases thanks to the increase of the flexibility of the posture of the cellular phone. By putting the folding cellular phone nearby the user with the angle between the speaker and microphone less than 180xc2x0 (normal lines of the speaker and microphone intersecting with each other at a specific point relatively near to the cellular phone), the cellular phone can conveniently be used for fully enjoying stereophonic sound reproduction of music etc.
In accordance with a fifth aspect of the present invention, in the third aspect, the display is provided to the display section so as to occupy approximately the total area of the side of the display section for the display, and the operation buttons are provided to the operation section so as to occupy approximately the total area of the side of the operation section for the operation buttons.
By such composition, the viewability of the display and the operability of the operation buttons can be improved to maximum in the folding cellular phone.
In accordance with a sixth aspect of the present invention, in the first aspect, the first signal-vibration transducer and the second signal-vibration transducer are implemented by flat-panel speakers.
By use of the low-profile flat-panel speakers as the signal-vibration transducers, the increase of the thickness of the cellular phone can be reduced to minimum despite the stacking structure of the cellular phone (in which the speaker is overlaid on the display and the microphone is overlaid on the operation buttons).
In accordance with a seventh aspect of the present invention, there is provided a cellular phone comprising radio telephone means, stereo sound reproduction means, a first signal-vibration transducer, a second signal-vibration transducer, and control means. The radio telephone means executes processes for the communication with radio base stations. The stereo sound reproduction means executes processes for stereophonic sound reproduction. The first signal-vibration transducer functions as a speaker of the cellular phone when the cellular phone is used for conversation, while functioning as one of stereo speakers when the cellular phone is used for sound reproduction. The second signal-vibration transducer functions as a microphone of the cellular phone when the cellular phone is used for conversation, while functioning as the other of the stereo speakers when the cellular phone is used for sound reproduction. The control means controls the connections of the signal-vibration transducers with the radio telephone means and the stereo sound reproduction means depending on whether the cellular phone is used for conversation or for sound reproduction.
In accordance with an eighth aspect of the present invention, in the seventh aspect, a display and operation buttons of the cellular phone are placed on a side of a housing of the cellular phone, and the first signal-vibration transducer and the second signal-vibration transducer are placed apart on the other side of the housing of the cellular phone.
In accordance with a ninth aspect of the present invention, in the eighth aspect, the housing includes: a display section including the display; an operation section including the operation buttons; and a hinge section connecting the display section and the operation section so that the cellular phone can be folded into a folded state in which the display faces the operation buttons and can be unfolded into an unfolded state in which the display is apart from the operation buttons.
In accordance with a tenth aspect of the present invention, in the ninth aspect, the housing is designed so that the angle between the display and the operation buttons in the unfolded state can be set larger than 180xc2x0.
In accordance with an eleventh aspect of the present invention, in the ninth aspect, the display is provided to the display section so as to occupy approximately the total area of the side of the display section for the display, and the operation buttons are provided to the operation section so as to occupy approximately the total area of the side of the operation section for the operation buttons.
In accordance with a twelfth aspect of the present invention, in the seventh aspect, the first signal-vibration transducer and the second signal-vibration transducer are implemented by flat-panel speakers.
In accordance with a thirteenth aspect of the present invention, in the seventh aspect, the stereo sound reproduction means receives radio signals from radio stations and reproduces the radio broadcasting.
In accordance with a fourteenth aspect of the present invention, in the thirteenth aspect, the stereo sound reproduction means receives FM signals from FM stations and reproduces the FM broadcasting.
In accordance with a fifteenth aspect of the present invention, in the seventh aspect, the stereo sound reproduction means receives streaming data from the Internet and reproduces the streaming sound.
In accordance with a sixteenth aspect of the present invention, in the seventh aspect, the cellular phone is designed to be connectable to an AC adapter for long time sound reproduction.
In accordance with a seventeenth aspect of the present invention, in the seventh aspect, the stereo sound reproduction means reads a sound file from a card-like medium and reproduces sound from the sound file.
In accordance with an eighteenth aspect of the present invention, in the seventh aspect, the stereo sound reproduction means obtains a sound file from another device through a cable and reproduces sound from the sound file.
In accordance with a nineteenth aspect of the present invention, in the seventh aspect, the cellular phone further comprises: a received sound amplifier for amplifying a received sound signal which is supplied from the radio telephone means; a transmitted sound amplifier for amplifying a sound signal to be transmitted which is supplied from the second signal-vibration transducer as the microphone; a first sound reproduction amplifier for amplifying one of stereo sound signals reproduced by the stereo sound reproduction means; and a second sound reproduction amplifier for amplifying the other of the stereo sound signals reproduced by the stereo sound reproduction means.
In accordance with a twentieth aspect of the present invention, in the nineteenth aspect, the cellular phone further comprises a first switch and a second switch. The first switch connects the first signal-vibration transducer with the output terminal of the received sound amplifier when the cellular phone is used for conversation. The first switch connects the first signal-vibration transducer with the output terminal of the first sound reproduction amplifier when the cellular phone is used for sound reproduction. The second switch connects the second signal-vibration transducer with the input terminal of the transmitted sound amplifier when the cellular phone is used for conversation. The second switch connects the second signal-vibration transducer with the output terminal of the second sound reproduction amplifier when the cellular phone is used for sound reproduction.